The researcher in me wants to debate, but I know that the work I do and that my colleagues do is better designed than a lot of "studies." So I agree with the vibe of the video and people have to be careful consumers of all information.
The findings of no one study are ever definitive. It takes decades of replication to even get to a point where we can trust results to 999/1000 cases with clinical trials and typically only to 95/100 cases in "action research" (which is not as tightly controlled). In research, we can never "prove" something 100%.
I will say this: don't throw out the baby with the bath water. While not ubiquitous, there are a few good studies on nutrition and exercise.
Complication makes it easy to explain failure.